NASA's GROVER roves over snow for over a month

NASA's autonomous, solar-powered explorer GROVER has been kitted out with ground-penetrating radar to take to Greenland's ice sheet on Friday. There the robot will spend a month analyzing the accumulation of snow and how this contributes to the ice sheet over time. The scientists involved hope to identify a new layer of ice that has formed since summer 2012, an unusually warm summer which saw melting across 97 percent of the area of the ice sheet. During that time, an iceberg twice the size of Manhattan calved from the Petermann Glacier, part of the ice sheet.

NASA hopes it can offset its ice accumulation data against summer melt to gauge net loss.

Though ice sheet may sound modest next to the word glacier, it is actually reserved for only the largest contiguous chunks of ice. While any sheet more than 50,000 sq km (19,000 sq miles) qualifies, the only two sheets existent today surpass that threshold by a country mile. Greenland's ice sheet covers 1.7 million sq km of the country's land area (almost all of it in other words). The Antarctic ice sheet is much larger again, covering 14 million sq km.

GROVER stands for both Greenland Rover and Goddard Remotely Operated Vehicle for Exploration and Research. The explorer came about as a result of two summer engineering bootcamps held at NASA's Goddard Space Flight Center in 2010 and 2011. Students pitched the idea of a solar-powered rover to Goddard glaciologist Lora Koenig, who became an adviser to the GROVER project. Equipping GROVER with radar was Koenig's idea; an alternative to using manned snow-going vehicles or aircraft which are more expensive to operate.

With solar panels attached, GROVER stands 6 feet (1.8 m) tall, and weighs in at 800 pounds (360 kg). Though the steep angle the PV panels are mounted at would compromise efficiency in most environments, on the snowy ice sheet, the high reflectance of the ground means this is much less of an issue. Because energy is at a premium, a low-power radar system has been used, and GROVER will trundle along at an average of 2 km/h (1.2 mph). Despite this modest speed (actually, not so bad given its working environment), it's thought that GROVER will be capable of gathering more data than a besnowmobiled human, thanks to the sun shining all day at these latitudes during the summer months.

Initially GROVER will stay within a 3-mile range of base camp where it will communicate with the research team over Wi-Fi. Once it's confirmed that all systems are GROVER, the robot will be let off the leash and its data recovered at the end of the summer. In the future, though, the researchers hope that GROVER will be able to report data in real time via satellite. Though capable of functioning autonomously, a satellite link would allow researchers to take control of GROVER remotely.